<!--
 * @Autor: Ruohong Yu
 * @Date: 2022-09-08 19:33:57
 * @Description: file content
 * @FilePath: \ebook\src\components\ebook\EbookLoading.vue
-->
<template>
  <div class="ebook-loading">
    <div class="ebook-loading-wrapper">
      <div class="ebook-loading-item" v-for="(item,index) in data" :key="index">
        <div class="ebook-loading-line-wrapper" v-for="(subItem,subIndex) in item" :key="subIndex">
          <div class="ebook-loading-line" ref="line"></div>
          <div class="ebook-loading-mask" ref="mask"></div>
        </div>
      </div>
      <div class="ebook-loading-center"></div>
    </div>
  </div>
</template>

<script>
import { px2rem } from '../../utils/utils'
export default {
  data () {
    return {
      data: [[{}, {}, {}], [{}, {}, {}]],
      maskWidth: [{ value: 0 }, { value: 0 }, { value: 0 }, { value: 0 }, { value: 0 }, { value: 0 }],
      lineWidth: [{ value: 16 }, { value: 16 }, { value: 16 }, { value: 16 }, { value: 16 }, { value: 16 }],
      add: true,
      end: false
    }
  },
  mounted () {
    this.task = setInterval(() => {
      this.$refs.mask.forEach((item, index) => {
        const mask = this.$refs.mask[index]
        const line = this.$refs.line[index]
        const maskWidth = this.maskWidth[index]
        const lineWidth = this.lineWidth[index]

        // 依次显示横线
        if (index === 0) {
          if (this.add && maskWidth.value < 16) {
            maskWidth.value++
            lineWidth.value--
          } else if (!this.add && lineWidth.value < 16) {
            maskWidth.value--
            lineWidth.value++
          }
        } else {
          if (this.add && maskWidth.value < 16) {
            const preMaskWidth = this.maskWidth[index - 1].value
            if (preMaskWidth >= 8) {
              maskWidth.value++
              lineWidth.value--
            }
          } else if (!this.add && lineWidth.value < 16) {
            const prelineWidth = this.lineWidth[index - 1].value
            if (prelineWidth >= 8) {
              maskWidth.value--
              lineWidth.value++
            }
          }
        }

        mask.style.width = `${px2rem(maskWidth.value)}rem`
        mask.style.flex = `0 0 ${px2rem(maskWidth.value)}rem`
        line.style.width = `${px2rem(lineWidth.value)}rem`
        line.style.flex = `0 0 ${px2rem(lineWidth.value)}rem`

        // 设置完整一次动画是否结束
        if (index === this.maskWidth.length - 1) {
          if (this.add) {
            if (maskWidth.value === 16) {
              this.end = true
            }
          } else {
            if (maskWidth.value === 0) {
              this.end = true
            }
          }
        }
        if (this.end) {
          this.add = !this.add
          this.end = false
        }
      })
    }, 20)
  }
}
</script>

<style lang="scss" scoped>
  .ebook-loading{
    position: relative;
    z-index: 400;
    width: px2rem(63);
    height: px2rem(40);
    background: transparent;
    border: px2rem(1.5) solid #d7d7d7;
    border-radius: px2rem(3);
    .ebook-loading-wrapper{
      display: flex;
      width: 100%;
      height: 100%;
      .ebook-loading-item{
        flex: 1;
        display: flex;
        flex-direction: column;
        padding: px2rem(7) 0;
        box-sizing: border-box;
        .ebook-loading-line-wrapper{
          flex: 1;
          padding: 0 px2rem(7);
          box-sizing: border-box;
          @include left;
          .ebook-loading-line{
            flex: 0 0 px2rem(6);
            width: px2rem(6);
            height: px2rem(2);
            background-color: #d7d7d7;
          }
          .ebook-loading-mask{
            flex: 0 0 px2rem(10);
            width: px2rem(10);
            height: px2rem(2);
          }
        }
      }
      .ebook-loading-center{
        position: absolute;
        left: 50%;
        top: 0;
        width: px2rem(1.5);
        height: 100%;
        background: #d7d7d7;
      }
    }
  }
</style>
